9mm or 40cal

9mm or 40cal ?

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Well I'm still debating on what caliber to get, I want to know what you all think I'm going to get a side arm for work and the way i see it people argue back and forth about what is a better caliber 9mm or 40cal I'm getting this for both on duty and for personal protection and as far as i can tell theirs not too much different between the two if there both using Hollow-point bullets but lets see what you guys say and pleas give the reason you selected the one you did or why you didn't pick the other caliber thank you

I voted for 9MM. I never cared much for .40 S&W (my own opinion, not an out-and-out dismissal of the cartridge), and I believe that most defensive situations can be handled as well with a 9MM as with a .40. In addition, 9MM is cheaper to shoot, therefore more apt to get more practice with it.

9mm. Because everyone I know who bought a .40 didn't keep it long. I don't know why (I carry .45) but that's what they did and, to the best of my knowledge, have not gone back. Seems like most went Glock 9mm but a few went to various .45s.

Main problem with .40 caliber pistols is that when the round was initially introduced, firearms companies were stuffing the round into guns designed specifically for the .9mm cartridge. Well, as some folks learned the hard way, the .40 S&W produces pressures that otherwise stock .9mm designs can't handle in the long run. So, .40 S&W pistols need to be bigger and heavier. And if that's the case, I'd rather have a .45 auto.

I'll take a 9mm in anything I possibly can. If I were considering a pistol that could be gotten in the same dimensions in 9, .40, or .45, I'd take the 9 every time. Ballistically, they're all extremely close in performance with top of the line hollowpoints. Why not stick with the one that has the flattest trajectory, highest capacity options, and that lends itself to quick and easy followup shots? Not to mention how cost effective it is to train with.

For the simple reason that you're asking, I'm going to say 9mm. Don't get the .40 unless you know exactly why you're getting it. Nothing against the .40 but the 9mm offers some advantages, mainly less recoil but also the price and variety of available ammo both for practice and "working" loads.

Some might say I'm compensating for something, but when I've had to carry a handgun for serious issues, a .45 has been most comforting. As I noted in another thread, I also own and have shot a 1911 in .38 Super and like it a lot. But I still like my old punkin chunker.

However, on the issue of 9mm v. .40 cal, I would have to throw my money on 9mm, I guess. The ammunition seems more widely available with a greater variety of loads. .40 seems to be one of those attempts at filling a gap. If the issue were stopping power, I think I would opt out of the whole mid-caliber debate and go with my old punkin cannon.

There used to be a .38/45 that I always wanted to try, but I never got around to it. It is a .45 ACP case necked down to take 9mm bullets. Conversion consisted of just a new barrel for a .45 ACP 1911. Not intended to be a hotrod wildcat round like the Super 9, it was said to be pretty accurate.

The OP mentioned for "on duty" - I assume both calibers are cleared for the job?

I suggest heading to the range and test-firing both calibers and see which one you like better.

There are plenty of arguments back and forth and plenty of pros and cons either way. For me, I prefer the power of heavier rounds over smaller and lighter. In close-ish quarters, if I only have one shot, I'd rather hit the target with a .45, a .40 S&W, and/or a 9mm. In that order.

But the arguments tend to break down thusly:
Magazine capacity. 9mm wins
Recoil. 9mm wins.
Cost. 9mm wins.
Stopping power. Heavily debated, but I'll err on the side of big. And it's the most important factor for me.

Depending on the make and model of your weapon, you might be able to find .22 conversion kits for practice and save the heavier ammo for specific training drills.

I'd say .40, on a lot of models I've shot I've not found a huge difference. I've also always been worried about the over penetration of the 9mm, there are many agency reports of it over penetrating and having less stopping power....hence many agencies stuck with .357, .45, or went with .40

I might be. I was being a bit tongue in cheek, but I would take a 9mm before a .40 or .45 any day of the week if I'm being honest. I've watched testing on ballistics gel with top of the line hollow points and you can measure the differences in overall tissue damage from each within a centimeter in most cases. The gap between the rounds has all but closed in performance. Basically the caliber war is talked about like the end of the world is on the line, but in the end all we do is make a tiny trade-off - A couple less rounds that probably aren't needed (most violent encounters end with only a few shots fired) for a bullet with hardly measurable better ballistics, or a marginally weaker round but pack a couple more ('cause "probably not needed" may not be good enough).

The main reason I take a 9mm in almost all cases is because out of the current pistol options on the market, I prefer the dimensions and features on the models that come in 9mm. It also doesn't hurt that it has the flattest trajectory of the bunch and the most cost effective training ammo.